Bokeh tool tip displaying all the values for the line - python-2.7

Question

I am trying to plot a line chart which includes tooltip, but the code below results in displaying all the values of the line in a tooltip instead displaying a single value for those co ordinates
#Import the library
import pandas
import itertools
import bokeh
import MySQLdb
from bokeh.plotting import figure, output_file, show
from bokeh.models import HoverTool
TOOLS='hover'
wells=['F1','F2','F3','F4','F5','F6','F7','F8','F9','F10','F11','F12','G1','G2','G3','G4','G5','G6','G7','G8','G9','G10','G11','G12']
p = figure(plot_width=800, plot_height=640,x_axis_type="datetime", tools=TOOLS)
p.title.text = 'Click on legend entries to hide the corresponding lines'
# Open database connection
db = MySQLdb.connect("localhost","user","password","db" )
#pallete for the lines
my_palette=bokeh.palettes.inferno(len(wells))
#create a statement to get the data
for name, color in zip(wells,my_palette):
stmnt='select date_time,col1,wells,test_value from db where wells="%s"'%(name)
#creating dataframe
df=pandas.read_sql(stmnt,con=db)
p.scatter(df['date_time'], df['test_value'], line_width=2, color=color, alpha=0.8, legend=name,)
#Inserting tool tip
hover = p.select(dict(type=HoverTool))
hover.tooltips = [("Wells","#wells"),("Date","#%s"%(df['date_time'])),("Values","#%s"%(df['test_value']))]
hover.mode = 'mouse'
#Adding a legend
p.legend.location = "top_right"
output_file("interactive_legend.html", title="interactive_legend.py example")
show(p)
Given below is the resultant screenshot
I am trying to get only one well,Date_time,Test_value at given mouse over instance

Answer 1

This code:
hover.tooltips = [
("Wells","#wells"),
("Date","#%s"%(df['date_time'])),
("Values","#%s"%(df['test_value']))
]
Does not do what you think. Let's suppose df['date_time'] has the value [10, 20, 30, 40]. Then after your string substitution, your tooltip looks like:
("Date", "#[10, 20, 30, 40]")
Which exactly explains what you are seeing. The #[10 part looks for a column named "[10" in your ColumnDataSource (because of the # in front). There isn't a column with that name, so the tooltip prints ??? to indicate it can't find data to look up. The rest 20, 30, 40 is just plain text, so it gets printed as-is. In your code, you are actually passing a Pandas series and not a list, so the string substitution also prints the Name and dtype info in the tooltip text as well.
Since you are passing sequence literals to scatter, it creates a Column Data Source for you, and the default names in the CDS it are 'x' and 'y'. My best guess, is that you actually want:
hover.tooltips = [
("Wells","#wells"),
("Date","#x"),
("Values","#y")
]
But note that you would want to do this outside the loop. As it is you are simply modifying the same hover tool over and over.